PING: Mike Jacoubowsky

[Qui si parla Campagnolo]

Sorni wrote:
> Qui si parla Campagnolo wrote:
>
> > Breaking a spoke is a syptom of an 'ill' wheel. The spoke broke for a
> > reason, most likely, the rim has gotten to the point that the spoke
> > tension is no longer 'even'...
>
> But what if a crash or rock or something nicks a spoke and weakens it (as
> appears to be the case in this case)? Can't the wheel still be "healthy"
> despite having a sick (or injured or broken) spoke?

Yes, the OP originally said he broke a spoke, not that a spoke was
damaged in the center of the spoke. Breaking spokes at the hub is
indeed a symptom of a sick wheel.

 

[Rick]

Mike Jacoubowsky wrote:
> >> Easy Mike, we don't sell them at all but have seen probably 4-5 broken
> >> spokes on these in the last 6 months. 'The rim should wear out first'
> >> doesn't really apply to just about any wheel these days...
> >
> > Perhaps he meant the rim should crack and fail at the spoke holes before
> > you break a spoke, which is what happened to my Bontrager Race Lite
> > Aero's after only 3600 miles. Different rim than the OPs, however.
>
> Exactly! Yeah, I know, I've seen that one. Definitely an issue with one of
> the extrusions, which has been fixed. Rims just don't seem all that
> difficult to make, so why all the issues? Like the Open Pros with the
> clicking eyelets. It's just an extrusion with eyelets, right? Seems like the
> manufacturers ought to get something completely right once, and then not
> change anything.

Gee, that should bring out Jobst. That is basically what he has been
saying for a while; they had it right with the MA2 then have gone
downhill with every change since ;-)

- rick

 

[[email protected]]

A Muzi wrote:
> >> Mike Jacoubowsky wrote:
> >>> Larry: I'm a bit concerned as to why you broke a spoke in the Bontrager Race
> >>> X-Lite. We've sold many hundreds of pair of those wheels, and spokes simply
> >>> don't break in them.
>
> Larry Coon <[email protected] wrote:
> >> Well, you can't say THAT any more.
>
> >> Mike Jacoubowsky wrote:
> >>> The rim should wear out first. How many miles?
>
> Larry Coon <[email protected]>
> > wrote: >> About 8,000 miles. No significant trauma, save for a crash
> >> about a year ago (wheel came out from under me in a turn).
> >> The spoke broke during a climb (about 7% grade, and I was
> >> seated & pedaling steady). The break was about 3" from the
> >> hub.
>
> [email protected] wrote:
> -snip-
> > About 90% of normal spokes (with elbows) break at the elbow, the rest
> > at the threads. In the only known spoke fatigue tests over 20 years
> > ago, 68 spokes broke at the elbow, and 8 broke at the threads, but
> > none broke in the middle:
> >
> > http://www.duke.edu/~hpgavin/papers/HPGavin-Wheel-Paper.pdf
> >
> > (Search for "stanford" or scroll down to page 10.)
> >
> > This is why butted spokes work fine--even their thinner midspans are
> > practically invulnerable in normal use. The parts of a spoke that are
> > bent during manufacture, assembly, and riding are at its ends.
> >
> > A spoke that breaks out in its midspan has probably been damaged by a
> > rock, a chain, or something else that the rider either didn't notice
> > or else forgot because the spoke fatigued slowly instead of breaking
> > right away.
>
> Agreed, that's an anomalous break. Gee I missed you guys!
>
> --
> Andrew Muzi
> www.yellowjersey.org
> Open every day since 1 April, 1971

Dear Andrew,

Glad to see you back.

Cheers,

Carl Fogel